Mn doped nanostucture ZnO thin film for photo sensor and gas sensor application Sandip V. Mahajan, Deepak S. Upadhye, Shahid U. Shaikh, Ravikiran B. Birajadar, Farha Y. Siddiqui et al. Citation: AIP Conf. Proc. 1512, 652 (2013); doi: 10.1063/1.4791206 View online: http://dx.doi.org/10.1063/1.4791206 View Table of Contents: http://proceedings.aip.org/dbt/dbt.jsp?KEY=APCPCS&Volume=1512&Issue=1 Published by the American Institute of Physics.
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Mn Doped Nanostucture ZnO Thin Film For Photo Sensor And Gas Sensor Application Sandip V. Mahajan2, Deepak S. Upadhye2, Shahid U.Shaikh1, Ravikiran B. Birajadar1, Farha Y.Siddiqui 1, Anil V. Ghule2,and Ramphal Sharma1, 2,* 1
Thin film and Nanotechnology Laboratory, Department of Physics, 2 Department of Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad-431004, (M. S.), India *Corresponding author:
[email protected] (Dr. Ramphal Sharma)
Abstract. Mn doped nanostructure ZnO thin film prepared by soft chemically route method. ZnO thin films were deposited on glass substrate by successive ionic layer adsorption and reaction technique (SILAR). After deposit ZnO thin film dipped in MnSO4 solution for 1 min. The optical properties as absorbance were determined using UV-Spectrophotometer and band gap was also calculated. The Structural properties were studied by XRD. The improvement in gas sensing properties was found to enhance after doping of Mn on ZnO thin film. The Photo Sensor nature was calculated by I-V characteristics. Keyword: Doping, SILAR, Structural, gas sensing, photo sensor. PACS: 78.66.-w, 72.40.+w, 73.50.Pz, 68.35.bg. were dipped in each precursor for 30sec, such 60 cycles were made. After prepared 0.01M MnSo4 solution and put the ZnO thin film for 1 min duration.
INTRODUCTION Various metal oxide semiconductors, like SnO2 and ZnO have been widely used for fabricating various types of gas sensors due to their versatile properties like wide energy band gap, higher transparency and low electron affinity. Doping is a widely used method for improving the opto-electrical properties of various semi conducting materials. Various materials like Al, Sn, P [1] etc. have doped into the ZnO matrix and have studied for various types of applications. Mn doped ZnO thin film were used ethanol sensor [2]. Mitra et al [3] have studied the effect of Pd dopant into the gas (LPG) sensing properties at 250oC. The effect of LPG sensing properties of spray deposited ZnO thin film at the operating temperature of 400 oC [4]. To reduce the operating temperature and to increase the response Mn was doped into the ZnO crystal. With these motivations, in the present study we have doped Mn into ZnO thin film by SILAR technique for (LPG) sensor which enhances its importance for cost effective device grade application point of view.
2. REULTS AND DISCUSSION 2.1 X-ray diffraction analysis The Fig. 1 shows the diffraction peaks observed close to 2θ = 31.6, 34.4, 36.2 and 56.56 are attributed to the (100), (002), (101) and (110) planes respectively of hexagonal ZnO, as can be seen in comparison with the JCPDS card No. 80−0075. The XRD data it is evident that, there are no additional peaks due to Mn2+ ions substitution. But the Mn doped ZnO thin film grain size increase to 24 nm [2].
1. EXPERIMENTAL ZnO thin films were deposited by SILAR technique. 0.02 M ZnSO4 solutions prepared in 50mL distilled water and it was used as cationic precursor. Distilled water was used as anionic precursor. Two to three drops of triethanolamine (TEA) was added to the ZnSo4 Solution. pH was kept at 10 by adding ammonia. The glass slides were cleaned by labolene and then rinsed by distilled water. The glass slides
FIGURE. 1. XRD pattern of Mn doped ZnO thin film.
SOLID STATE PHYSICS: Proceedings of the 57th DAE Solid State Physics Symposium 2012 AIP Conf. Proc. 1512, 652-653 (2013); doi: 10.1063/1.4791206 © 2013 American Institute of Physics 978-0-7354-1133-3/$30.00
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2.2 Optical Studies 2.3 Photosensitivity Fig. 2 shows absorbance spectra and band obtained from Mn doped ZnO thin film. But doping concentration increase band gap decreases From absorbance figure the energy band gap of doped ZnO thin film was found 3.24 eV.
gap the [2]. Mn
Fig.3 shows I-V graphs for Mn doped ZnO thin films in dark condition and under the illumination of lamp (60 Watt) light. In general the photocurrent generated by charge carriers increases with the increasing power or intensity of the incident light. It means the current increases under the illumination of light compare to the dark condition. The effect of the light on the films shows their obtained Mn doped ZnO thin films can be used as a photo sensor material.
2.4 Gas Sensor Properties Figure 4 shows the response curve of Mn doped ZnO thin film at operating temperature of 200 oC and at 200 ppm of LPG gas. Proper substitution of Mn increases the crystallite size, decreases the grain boundary. In this case, Mn may work like a bridge in case of flowing of electron which may enhance the sensing property of Mn doped ZnO thin film. The fast response and recovery times (~8 sec and 10 sec respectively) were the main feature in this case. As the gas concentration enhanced the response was found to increase.
FIGURE.2. Optical band gap of Mn doped ZnO thin film
2.3 Photosensitivity
.
ACKNOWLEDGMENTS The authors are thankful to the Head, department of Physics and Nanotechnology, Dr. Babasaheb Ambedkar Marathwada University, Aurangabad for providing the laboratory facility to carry out the research work. FIGURE. 3. I-V Characteristics Mn doped ZnO thin film.
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Kobayashi, O. F. Sankey, and J. D. Dow, Phys.Rev B 28, 946 (1983). D. Sivalingam, J. B. Gopalakrishnan, J. B. Balaguru Rayappan, Sens. Actuators B 166– 167, 624– 631 (2012) P. Mitra and H. S. Maiti, Sens. Actuators B 97, 4958 (2004). V. R. Shinde, T. P. Gujar, and C. D. Lokhande, Sens. Actuators B 120, 551–559. (2006)
FIGURE. 4. Gas sensing properties of Mn doped ZnO thin film
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